Can you support this assumption with actual facts and reliable statistics?

"You are what you are - accept it" in nature there are several species of birds, mamals, reptiles and amphibians that can change gender therefore is it not totally unfeasible that written into our own DNA is the same (mostly latent) code? Who's to say transgendered people are not transgendered from birth, you have heard of hermaphrodites surely; well isn't is also possible that there are no external signs other than brain chemistry version of this?

women have a thicker corpus callosum (the join between the hemispheres), and people extrapolate from this "women are better at multitasking", but there is no evidence of this or any other functional difference. There is of course a cultural difference between male and female brains, i.e. you can be brought up as a boy or a girl, but that's just shit we make up for ourselves during our lifetime. So I think Vagabond is basically right, except that I am on principle opposed to accepting anything at all ever and I look to a future where we all grow tentacles.

If you're talking about early development, that's a physical difference

If you're suggesting that men who want gender realignment have naturally high levels of estrogen, well, we could test for that, so I assume they don't. And I think females have more because of ovaries, not sure how much of it is made in the brain.You got testosterone right. Which makes me wonder about "Brian chemistry".

No I was talking about levels of Oestrogen that was present in the Mother during pregnancy

and there are tests that have proven this to be the case but this can only be decided post-mortem - so what kill all transexuals cut open their brain "Oops sorry this one was actually transgendered and not under a dillusion!"

also even if it is "a mental problem" (which i doubt), a mental problem is still a serious problem which causes real pain and suffering and physical symptoms, and you don't cure mental problems by just telling people to get over it.